Recent studies have shown that prior to harvest, corn can become highly contaminated with the mold, Aspergillus flavus. The extent and degree of the contamination have been linked to weather conditions and damage to the ears by insects. The mold can become established on the surface of the kernels or, if the insects bore a hole in the kernel to lay eggs, internal contamination of the kernels also occurs. Along with a number of other metabolites, Aspergillus flavus produces several compounds called alfatoxins B1, G1, B2, and G2 which are among the most toxic and carcinogenic substances known. While many of the effects of aflatoxin ingestion have been well documented, the effects of inhaling aflatoxins are largely unknown. Two reports have suggested the association of the inhalation of aflatoxins by research workers with health impairment. The abrasive actions of the harvesting processes are likely to dislodge a fraction of the aflatoxin from the kernels and create a serious inhalation health hazard to combine operators, truckers and grain handlers. The purpose of this project is to determine the levels of airborne aflatoxins, to measure worker exposure levels and to assess worker health effects. The aflatoxin level will be measured in the total dust, the respirable dust from the eight stages of an Andersen sampler and breathing zone samples. Prior to harvest, corn fields in regions which have frequently shown high contaminations will be screened and the ten fields with the highest aflatoxin contamination will be selected for study. Worker exposure levels at two commercial grain elevators in the area receiving the contaminated corn will also be measured. Based on the data collected, conclusions will be prepared dealing with the needs for personal protection and the needs for future toxicological, medical and epidemiological studies.